perf test: Fix build on older glibcs

perf test: Fix build on older glibcs

Where we don't have CPU_ALLOC & friends. As the tools are being used in older
distros where the only allowed change are to replace the kernel, like RHEL4 and
5.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>